WiFi connectivity slows, then fails

My device is fully up to date with the latest OS release and has minimal apps installed, all sourced from Amazon's official app store. The device has not been rooted, no apps are side loaded.

After anywhere from 10 minutes to 2 hours, page loads on apps that require internet slows to a crawl. Videos won't play, just buffer, buffer, buffer.

I see nothing unusual in the amount of memory being used when the Kindle is performing vs running slow.

WiFi Analyzer app shows a good connection to my home router and all other wireless devices in the household, including 3 other Kindles do not experience performance issues while connected.

Power cycling the device solves the problem immediately but then the issue repeats.

Is it possible the WiFi card is loose or failing? If it is, is it a repair I can do myself? How might I go about figuring out exactly what the problem is?

I'm pretty handy and recently replaced a broken screen on a Kindle Keyboard 3G so I'm comfortable cracking the case to DIY.

Thanking you in advance for your attention to my questions.